Data latency is the time it takes data to travel from its source and become available in a database for processing. High latency is a slow transmission of data, whereas a low latency means the data transfer is faster. The faster you receive the information, the faster it can be processed, and actionable insights can be obtained, so the goal is to get data from a low latency source.

When it comes to understanding what is happening on the roads, low latency is essential. Delays in traffic information and roadway incident reports can skew trends and negatively impact response times, which in some cases can be life or death scenarios. Therefore, latency is critical to evaluate when it comes to choosing the best data source.

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What affects latency?

There are four key areas that affect data latency

Transmission - The speed at which the data is transmitted to a destination from the source.  Data transmitted over mobile telephone networks can suffer from issues we are all familiar with regarding cell phone reception. For example, some areas have poor reception and other areas are very busy with many devices trying to communicate at the same time resulting in dropout.

Reception - A centralised logging process running in a cloud computing system for example, must receive the new data and add it to a catalogue of data available for processing. Depending on data volumes this step can involve queuing systems to ensure that data is kept in order and not discarded.

Validation - Following data reception are multiple stages of data validation. A data exchange platform will validate each data point received and identifies several ways in which data may be invalid and this can take time.

Enrichment - The final stage prior to the data becoming available to users is enrichment. Here, enrichment systems will classify or declassify data to standardise it in some way.

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How data latency differs between mobility data sources

Mobile phone - Mobile phone data can be very low latency if there is good reception, but constant streams of data are costly for the consumer and eat into battery life. This means that data is often only sent every 30 seconds or every minute. If a mobile phone in a vehicle experiences a sudden slowdown, then that may not be transmitted for quite some time following the actual event.

Roadside sensors - Being physical infrastructure with a high cost of installation, some sensors will have been in position for several years. Though there are high speed and low latency systems available for gathering roadside data, many may not yet have been upgraded. Some of the older systems may only report data overnight via telephone or only send data on a schedule such as every fifteen minutes.

Connected Vehicles - Connected cars, like all connected devices, generate a huge amount of data. Connected vehicle data is created from each connected vehicle’s built-in sensors, which provides information from the vehicle itself at any given moment – from the vehicle’s speed, to when and where drivers are braking. CVD provides low latency data, which means information is instantaneously processed from the vehicle and is made available to users in 60 seconds or less. This speed enables organizations using CVD to make near real-time decisions based on what is happening on the roads.  

We believe that cars know more about the roads than we do and that CVD is the best source of data when it comes to understanding what is happening on the roads.

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